KR20140053378A - Lithium rechargeable battery - Google Patents

Abstract

The lithium secondary battery of the present invention comprises a current collector and an active material layer containing active material particles (10) held on the current collector. The active material particle (10) is a secondary particle (14) having a plurality of primary particles (12) of a lithium-transition metal oxide. The active material particle has a hollow portion (16) formed on the inner side of the secondary particle And a shell portion (15) surrounding the base portion (16). The secondary particle 14 has a through hole 18 penetrating from the outside to the hollow portion 16. The ratio (A / B) of the half width A of the diffraction peak obtained by the (003) plane to the half width B of the diffraction peak obtained by the (104) plane in the powder X-ray diffraction pattern of the active material particle 10 ) Satisfies the following formula: (A / B)? 0.7.

Description

 LITHIUM RECHARGEABLE BATTERY [0002]

The present invention relates to a lithium secondary battery. More particularly, the present invention relates to a lithium secondary battery comprising active material particles constituted by a lithium transition metal oxide.

The present invention also claims priority to Japanese Patent Application No. 2011-189422 filed on August 31, 2011, the entire contents of which are incorporated herein by reference.

In recent years, lithium-ion batteries, nickel-metal hydride batteries and other secondary batteries have become increasingly important as power sources for in-vehicle power sources or power sources for personal computers and portable terminals. Particularly, a lithium secondary battery which is light in weight and has a high energy density is preferably used as a high output power source for in-vehicle use. The lithium secondary battery is provided with a material (active material) capable of reversibly intercalating and deintercalating lithium ions (Li ions) in its electrode, and charging and discharging are performed by the passage of Li ions between the electrodes of the lithium ion secondary battery. As typical examples of the active material (positive electrode active material) used for the positive electrode of such a lithium secondary battery, there can be mentioned lithium-transition metal oxides including lithium and transition metal elements. For example, a lithium transition metal oxide (as a nickel-containing lithium transition metal oxide) containing at least nickel (Ni) is preferably used as the transition metal element having a layered crystal structure. As a technical literature on the active material of a lithium secondary battery, Patent Document 1 can be cited.

Japanese Patent Laid-Open No. 08-321300

However, in a vehicle such as a so-called hybrid vehicle or an electric vehicle, in which a wheel is driven by an electric motor, it is possible to travel only by the electric power accumulated in the battery. In such a battery, the output tends to decrease as the state of charge (SOC) decreases. In order to stabilize running, it is preferable to use the battery within a predetermined SOC range. If the battery mounted on such a vehicle can exhibit the necessary output even in the low SOC region, it is possible to improve the running performance of a hybrid vehicle, an electric vehicle and the like. Also, if the required output can be exhibited even in the low SOC region, the number of batteries for securing the required energy amount can be reduced, and the cost can be reduced.

A lithium secondary battery according to the present invention includes a current collector and an active material layer containing the active material particles held in the current collector. The active material particle is a secondary particle having a plurality of primary particles of a lithium-transition metal oxide, and constitutes a hollow structure having a hollow portion formed inside the secondary particle and a shell portion surrounding the hollow portion. In the secondary particle, a through hole penetrating from the outside to the hollow portion is formed. The half-width width A of the diffraction peak obtained by the (003) plane and the half-width of the diffraction peak obtained by the (104) plane in the powder X-ray diffraction (X-ray diffraction) pattern of the active material B ratio (A / B) satisfies the following formula: (A / B)? 0.7.

Generally, a lithium-transition metal oxide such as LiNiO ₂ has a laminated structure in which a Li layer, an O layer, a transition metal layer, and an O layer are repeatedly overlapped, and Li Ions are occluded and released. If the crystal thickness in the direction orthogonal to the c-axis is too large, the diffusion distance of Li ions becomes long, so that diffusion of ions into the crystal becomes slow. Further, when a plurality of primary particles containing the above-described crystal are aggregated to form secondary particles, diffusion of Li ions is inhibited by the presence of grain boundaries in the particles. Such a decrease in the Li ion diffusibility can be a cause of deterioration in performance of the battery (for example, deterioration in output characteristics). Particularly, in the low SOC region, the Li ion concentration in the active material is high and the diffusion of ions into the active material during rate of discharge becomes susceptible to such deterioration.

According to the present invention, in the powder X-ray diffraction pattern of the active material particles, the ratio (A / B) of the half width A of the diffraction peak obtained by the (003) plane to the half width B of the diffraction peak obtained by the ) Is 0.7 or less, the thickness of the crystal in the direction orthogonal to the c-axis is extremely thin as compared with the conventional active material particle having a half-width ratio (A / B) of more than 0.7. As a result, the diffusion distance of Li ions is short and diffusion of Li ions into crystals is fast. Further, since the hollow portion is formed in the secondary particles having a plurality of primary particles containing the crystal, aggregation of the primary particles is less than that of the solid dense structure. As a result, the grain boundaries in the grains are small and the diffusion of Li ions into the grains is faster. As a result, the lithium secondary battery constructed using the active material particles can stably exhibit a high output even in a low SOC region (for example, when the SOC is 30% or less).

In one preferred form of the technique disclosed herein, the half width ratio (A / B) satisfies (A / B)? 0.7. Preferably, (A / B)? 0.65, and more preferably (A / B)? 0.6. If the half width ratio (A / B) is too large, the thickness of the crystal in the direction orthogonal to the c-axis becomes thick and the diffusion of ions into the crystal becomes slow, so that necessary output characteristics may not be obtained. On the other hand, the active material particles having too small a half width ratio (A / B) are difficult to be produced (synthesized), and in addition, crystal growth (particularly growth in a direction orthogonal to the c axis) becomes insufficient, The metal in the active material may be eluted into the electrolytic solution during storage. If the metal is eluted in the electrolyte, the battery capacity may be lowered. (A / B) is preferable, and 0.5? (A / B) is preferable from the viewpoint of suppressing deterioration of capacity at high temperature storage.

In a preferred embodiment of the lithium secondary battery disclosed herein, the average thickness of the shell portion surrounding the hollow portion of the active material particles is 2.2 占 퐉 or less. According to this configuration, the thickness of the shell portion surrounding the hollow portion of the active material particles is very thin. As a result, the diffusion of Li ions into the shell portion of the active material particles is fast, and the above-mentioned effect can be more appropriately exerted. The lower limit value of the average thickness of the shell portion is not particularly limited, but may be generally 0.1 탆 or more. By setting the average thickness of the shell portion to 0.1 mu m or more, durability necessary for the active material particles is ensured, and the performance of the lithium secondary battery is stabilized.

In a preferred embodiment of the lithium secondary battery disclosed herein, the lithium transition metal oxide is a layered crystal structure compound containing at least nickel as a constituent element. The lithium transition metal oxide may be a layered crystal structure compound containing, for example, nickel, cobalt and manganese as constituent elements. The lithium transition metal oxide may be a layered crystal structure compound containing tungsten. In this case, the content of the tungsten is preferably 0.05 mol% to 1 mol% when the total amount of the transition metal elements other than tungsten in the compound is 100 mol% in terms of the molar percentage. With such a content of tungsten, the above-described half width ratio (A / B) can be suitably controlled within the preferable range disclosed herein.

Preferably, the lithium transition metal oxide is represented by the following general formula:

<Formula 1>

Li _{1 + x} Ni _y Co _z Mn _{(1- y z )} W _留 M _硫 O ₂

Of a layered crystal structure.

The value of x in the formula 1 is 0? X? 0.2, the value of y is 0.1 <y <0.9, the value of z is 0.1 <z <0.4, the value of? Is 0.0005??? 0.01, The value of? is 0??? 0.01. M in the above formula is an additive element and is not present or is one or more elements of Zr, Mg, Ca, Na, Fe, Cr, Zn, Si, Sn, Al, B and F. It is particularly preferable that x in the above formula is a real number satisfying 0.05? X? 0.2. It is particularly preferable that? In the above formula is a real number satisfying 0.001??? 0.01 (more preferably 0.002?? 0.01, and further 0.005?? 0.01).

Further, the present invention provides a method for suitably preparing the above-mentioned active material particles. That is, the production method of the present invention is a secondary particle having a plurality of primary particles of a lithium-transition metal oxide, the secondary particle having a hollow portion formed inside the secondary particle and a shell portion surrounding the hollow portion, The particle is a method of producing a hollow structure active material particle having a hole in which a through hole penetrating from the outside to the hollow portion is formed.

Specifically, the method for producing an active material particle described herein comprises the steps of supplying ammonium ions to an aqueous solution (typically an aqueous solution) of a transition metal compound to precipitate transition metal hydroxide particles from the aqueous solution Process). Here, the aqueous solution contains at least one transition metal element constituting the lithium transition metal oxide. The manufacturing method, also, is 1.05 to 1.2, the fine mixture castle that said transition comprises a metal hydroxide and a lithium compound, lithium total of (Li) and all the other constituent metal elements molar ratio of _{(M all) (Li / M} all) (1.05 or more and 1.2 or less). And firing the mixture in the range of 700 ° C to 1000 ° C under the condition of setting the maximum firing temperature to obtain the active material particles (firing step). According to this production method, in the powder X-ray diffraction pattern of the active material particles, the ratio (A) of the half-width width A of the diffraction peak obtained by the (003) plane to the half width B of the diffraction peak obtained by the / B) satisfies the following formula: (A / B)? 0.7. This production method can be suitably employed, for example, as a method for producing any one of the active material particles disclosed herein.

It is preferable that the firing step is performed so that the maximum firing temperature is 850 to 950 占 폚 and the firing time is 3 to 20 hours. As a result, it is possible to more easily manufacture a hollow structure active material particle having a hole having a half width ratio (A / B) of 0.45? (A / B)? 0.7.

The transition metal hydroxide may include tungsten. In this case, the content of the tungsten is preferably 0.05 mol% to 1 mol% when the total amount of the transition metal elements other than tungsten in the transition metal hydroxide is 100 mol% as a molar percentage. As a result, it is possible to more easily manufacture a hollow structure active material particle having a hole having a half width ratio (A / B) satisfying (A / B)? 0.7.

The raw hydroxide producing step comprises a nucleation step of precipitating the transition metal hydroxide from the aqueous solution and a grain growing step of growing the transition metal hydroxide in a state where the pH of the aqueous solution is lower than the nucleation step . In this case, the pH of the aqueous solution in the nucleation step is preferably 12 or more and 13 or less. Further, it is preferable that the pH of the aqueous solution in the particle growing step is 11 or more and less than 12.

As described above, any one lithium secondary battery disclosed herein can stably exhibit a high output even in a low SOC region (for example, when the SOC is 30% or less), and therefore, for example, (Typically, a battery for driving power). Thus, according to the present invention, there is provided a vehicle comprising any one of the lithium secondary batteries disclosed herein (which may be in the form of a battery pack to which a plurality of batteries are connected). Particularly, a vehicle provided with the lithium secondary battery as a power source (for example, a plug-in hybrid vehicle (PHV) or an electric vehicle (EV) capable of charging with a household power source) is provided.

1 is a cross-sectional view schematically showing active material particles used in an embodiment of the present invention.
2 is a view showing an example of a powder X-ray diffraction pattern of a layered crystal structure lithium-transition metal oxide.
3 is a diagram schematically showing a lithium secondary battery according to an embodiment of the present invention.
4 is a view for explaining a wound electrode body used in an embodiment of the present invention.
5 is a graph showing the relationship between the half width ratio (A / B) and the output characteristics.
6 is a graph showing the relationship between the half width ratio (A / B) and the capacity retention ratio after high temperature storage.
7 is a graph showing the relationship between the maximum firing temperature and the half width ratio (A / B).
8 is a graph showing the relationship between the firing time and the half width ratio (A / B).
9 is a graph showing the relationship between the amount of addition of W and the half width ratio (A / B).
10 is a graph showing the relationship between Li / _Mall ratio and half width ratio (A / B).
11 is a side view schematically showing a vehicle equipped with a lithium secondary battery.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Each drawing is schematically drawn and does not necessarily reflect the reality. The matters necessary for carrying out the present invention as matters other than those specifically mentioned in this specification can be understood as a design matter of a person skilled in the art based on the prior art in the field. The present invention can be carried out based on the contents disclosed in this specification and the technical knowledge in the field.

The positive electrode active material particles 10 (FIG. 1) used in the lithium secondary battery according to the present embodiment include a lithium transition metal oxide having a layered salt-salt type structure in which the crystal structure belongs to a hexagonal system, and a powder X-ray diffraction pattern (A / B) of the half width A of the peak obtained by the diffractive surface of the Miller index (003) and the half width B of the peak obtained by the diffractive surface of the Miller index 104 satisfies the following formula: A /B)&lt;0.7.

<Powder X-ray Diffraction Pattern>

Here, X-ray diffraction (XRD) measurement using a CuK? Ray can be performed by irradiating X-ray source (CuK? Ray) onto a sample surface of a sample. The sample surface may be a surface including positive electrode active material particles 10 (typically powder), or may be a surface (positive electrode active material layer surface) on which a positive electrode is formed by binding the positive electrode active material particles 10 with a binder. At this time, the incident angle to the sample may be changed stepwise or continuously while rotating the sample on the predetermined scanning axis, and the X-ray may be irradiated, and the X-ray diffracted by the sample may be captured by the inspection device. Then, the angular difference (diffraction angle 2?) Between the diffraction direction of the X-ray and the incidence direction and the diffracted X-ray intensity are measured. Such X-ray diffraction measurement can be performed using an X-ray diffraction measurement apparatus commercially available from various measurement apparatus manufacturers. For example, an X-ray diffractometer MultiFlex manufactured by Rigaku may be used.

In Figure 2, there is shown an X-ray diffraction pattern in the case where the positive electrode active material particles 10 of _{LiNi 1/3 Co 1/3} Mn 1/3 O 2. The diffraction pattern of _{LiNi 1/3 Co 1/3} Mn 1/3 O 2, there occurs a diffraction peak to diffraction originated each at 18 ℃ (003) surface. Further, a diffraction peak originating from the (104) plane occurs near the diffraction angle of 45 캜. From the diffraction pattern thus obtained, the half width A of the diffraction peak derived from the (003) plane and the half width B of the diffraction peak derived from the (104) plane can be calculated. The calculation of these half-value widths A and B can be performed using analysis software provided by an X-ray diffraction measuring apparatus commercially available from various measurement apparatus manufacturers. For example, an analysis software JADE attached to an X-ray diffraction measurement apparatus manufactured by Rigaku Corporation can be used.

The positive electrode active material particle 10 provided by the present invention is characterized in that in the powder X-ray diffraction pattern, the half width A of the diffraction peak obtained by the (003) plane and the half width B (A / B) of 0.7 or less is preferable, but it is preferably 0.65 or less, and particularly preferably 0.6 or less.

As described above, the active material particle 10 having the half width ratio (A / B) of 0.7 or less has a larger thickness in the c-axis direction than the conventional active material particles having a half width ratio (A / B) And the thickness in the direction orthogonal to the c-axis becomes thinner. As a result, the surface on which Li ions can be inserted is increased, and the ion diffusion distance in the crystal is shortened. According to the active material particle having such a constitution, since the diffusion of Li ions into the crystal is rapid, Li ions are easily released from the inside of the crystal during charging, and Li ions are liable to be absorbed into the inside of the crystal at the time of discharging. Therefore, by using the positive electrode active material particles having such a half width ratio (A / B) as described above, the output characteristics (particularly, the output characteristics in the low SOC region) of the lithium secondary battery can be improved.

&Lt; Half width ratio (A / B) >

As the positive electrode active material particle described herein, it is preferable that the above half-width ratio (A / B) satisfies 0.45? (A / B)? 0.7 and more preferably satisfies 0.45? (A / B)? 0.65 , And particularly preferably 0.45? (A / B)? 0.6. On the other hand, the active material particles having a half width ratio (A / B) of less than 0.45 have difficulty in producing (synthesizing) crystal growth (in particular, growth in a direction perpendicular to the c axis) , The metal in the active material may be eluted into the electrolytic solution at the time of high-temperature preservation. If the metal is eluted in the electrolyte, the battery capacity may be lowered. (A / B)? 0.7 (particularly 0.5? (A / B)? 0.7) from the viewpoint of suppressing deterioration of capacity at high temperature storage. For example, the active material particles having a half-width ratio (A / B) of 0.5 or more and 0.7 or less (particularly 0.55 or more and 0.65 or less) are suitable from the viewpoints of both improving output characteristics and suppressing high-temperature storage deterioration.

Further, the adjustment of the half width ratio (A / B) can be performed by various methods. For example, as a method for further reducing the half width ratio (A / B): a method for reducing the half width ratio (A / B) to a raw material (a mixture of a transition metal hydroxide and a non- the larger the Li / M _all in more; The firing temperature at the time of synthesis is lowered; The firing time at the time of synthesis is made shorter; A small amount of tungsten (W) as an additive element is added to the raw material; And the like can be exemplified. These methods can be employed singly or in appropriate combination.

<Hollow structure>

1, the positive electrode active material particle 10 is a hollow structure having secondary particles 14 and a hollow portion 16 formed on the inner side thereof. And a through hole (18) passing through the through hole (16) is formed. The secondary particles 14 have a form in which the primary particles 12 containing crystals as described above are gathered into a spherical shape. In a preferred form, the active material particles 10 have a shape in which the primary particles 12 are connected in a circular shape (bead shape) on a cross-sectional SEM (Scanning Electron Microscope) thereof. The active material particles 10 may be in the form of primary particles connected to each other (single layer) or two or more primary particles connected to each other (multilayered). In the case where two or more primary particles overlap each other, it is preferable that the number of the primary particles 12 is about 5 or less (for example, 2 to 5), and about 3 or less More preferably 2 to 3). It is particularly preferable to employ a form in which the primary particles 12 are connected in a single layer.

As described above, the hollow active material particles (10: secondary particles) in which the primary particles 12 are connected in a single layer or in multiple layers have less aggregation of the primary particles 12 as compared with a compact structure having no cavities therein. As a result, the grain boundaries in the grains are small (further, the diffusion distance of Li ions is shorter), and diffusion of Li ions into the grains is faster. Therefore, when such hollow active material particles 10 having such a small grain boundary are used, the diffusion of Li ions into the crystal becomes faster (due to the synergistic effect) due to the above-described half width ratio (A / B) The output characteristics of the lithium secondary battery can be remarkably improved. For example, a lithium secondary battery showing good output even in a low SOC region (for example, when the SOC is 30% or less) in which ion diffusion into the active material is controlled can be constructed.

Further, according to the study by the inventors of the present invention, the improvement in the output in the low SOC region by defining the above-mentioned half-width ratio (A / B) to the preferable range described herein is that the active material particles of dense structure And the same degree of effect can not be obtained when used. Therefore, by applying the above-described half-width ratio (A / B) specification and the hollow structure active material particles in combination, it is possible to obtain a synergistic effect by the combination of the low SOC region (for example, when the SOC is 27% A lithium secondary battery having greatly improved output characteristics can be provided.

<Average thickness of shell part>

In this case, the average thickness of the shell portion 15 (the portion where the primary particles 12 are gathered into a spherical shape) surrounding the hollow portion 16 is suitably, for example, 2.2 탆 or less, more preferably 1.5 Mu m or less. The thinner the thickness of the shell portion 15, the shorter the diffusion distance of Li ions is, and the faster the diffusion of Li ions into the shell portion 15 becomes. As a result, the internal resistance (in particular, the internal resistance in the low SOC region) can be lowered. The lower limit value of the average thickness of the shell portion 15 is not particularly limited, but may be generally 0.1 탆 or more. By setting the average thickness of the shell portion 15 to 0.1 mu m or more, the strength required for the positive electrode active material particles 10 is obtained. When the release and absorption of Li ions are repeated in the positive electrode active material particles 10, expansion and contraction occur. Sufficient strength can be ensured even for such expansion and contraction. As a result, the durability of the positive electrode active material particles 10 is improved, and the performance of the lithium secondary battery can be stabilized over time. From the viewpoint of achieving both the internal resistance reducing effect and durability, it is preferable that the average thickness of the shell portion 15 is approximately 0.1 탆 to 2.2 탆, more preferably 0.2 탆 to 1.5 탆, particularly preferably 0.5 탆 to 1 Mu m.

The average thickness of the shell portion can be grasped by observing the cross section of the positive electrode active material particles with an SEM. The thickness of the shell portion 15 at an arbitrary position k of the inner side surface 15a of the shell portion 15 is set to be larger than the thickness of the shell portion 15 on the inner side surface (K) from an arbitrary position k of the shell portion 15a to the outer surface 15b of the shell portion 15. [ The value of the average thickness of the shell portion 15 is obtained, for example, by grasping the thickness at an arbitrary position k of at least 10 inner sides and obtaining an arithmetic mean value thereof.

&Lt; Average particle diameter of primary particles &

In addition, the average thickness of the preferable shell portion 15 may also be different depending on the average particle diameter of the primary particles 12. The average thickness of the shell portion 15 is preferably 5 times or less the average particle diameter of the primary particles 12 and more preferably about 4 times or less (for example, about 2 times or less). The average particle diameter of the primary particles constituting the positive electrode active material particles described herein may be in the range of approximately 0.1 탆 to 0.6 탆. It is preferable that the particles are primary particles having an average particle diameter of about 0.2 탆 to 0.5 탆. According to this configuration, since the average thickness of the shell portion 15 is very thin, the above-described effect can be more appropriately exerted. The average particle diameter of the primary particles can be determined by a method known in the art, for example, by surface SEM measurement of the active material.

&Lt; Average particle diameter of secondary particles &

It is preferable that the average particle diameter of the positive electrode active material particles 10 (here, median diameter D50, hereinafter the same) is approximately 2 to 25 占 퐉. According to the positive electrode active material particles 10 having such a configuration, good battery performance can be exhibited more stably. For example, if the average particle diameter is too small, the volume of the hollow portion 16 is small, so that the effect of improving battery performance tends to decrease. And more preferably an average particle diameter of about 3 탆 or more. From the viewpoint of productivity and the like of the positive electrode active material particles, the average particle diameter is preferably about 25 탆 or less, more preferably about 15 탆 or less (for example, about 10 탆 or less). In a preferred form, the average particle size of the positive electrode active material particles is approximately 3 탆 to 10 탆. The average particle diameter of the positive electrode active material particles can be determined by measurement based on a method known in the art, for example, a laser diffraction scattering method.

<Through hole>

The positive electrode active material particle 10 has a through hole 18 penetrating the secondary particle 14 (the shell portion 15) from the outside to the hollow portion 16, as shown in Fig. According to such positive electrode active material particles 10, the electrolytic solution easily passes through the hollow portion 16 and the outside through the through hole 18, so that the electrolyte solution in the hollow portion 16 is appropriately replaced. This makes it difficult for the liquid to run out of the electrolyte solution in the hollow portion 16. Thus, in the hollow portion 16, the primary particles 12 of the positive electrode active material can be more actively utilized. According to such a constitution, the diffusion of Li ions into the crystal is fast due to the definition of the above-mentioned half width ratio (A / B), and the fact that the electrolyte spreads evenly over the primary particles 12 containing the crystals (By the synergistic effect), the output characteristics (particularly, the output characteristics in the low SOC region) of the secondary battery can be further improved.

In this case, the opening width h of the through hole 18 may be an average of not less than 0.01 mu m on the average of the positive electrode active material layer. The opening width of the through hole 18 is the diameter of the narrowest portion in the path from the outside of the positive electrode active material particle 10 to the hollow portion 16 of the through hole 18. The electrolyte solution 90 (see FIG. 3) can be sufficiently introduced into the hollow portion 16 from the outside through the through hole 18 if the opening width of the through hole 18 is 0.01 μm or more on average. As a result, the effect of improving the battery performance of the lithium secondary battery can be more suitably exhibited. When there are a plurality of through holes 18, it may be evaluated as a through hole having the largest opening width among the plurality of through holes 18. [ The opening width h of the through hole 18 may be 2.0 mu m or less on average, more preferably 1.0 mu m or less on average, and more preferably 0.5 mu m or less on average.

The number of the through holes 18 may be on the order of 1 to 20 on average per one particle of the positive electrode active material particles 10, and more preferably about 1 to 5 on average. According to the positive electrode active material particles 10 having such a structure, good battery performance can be exhibited more stably. The number of the through holes 18 of the hollow positive electrode active material particles 10 having holes is determined by, for example, grasping the number of through holes per particle for at least 10 or more of the optionally selected positive electrode active material particles, The average value can be obtained.

<Composition of Lithium Transition Metal Oxide>

The lithium transition metal oxide constituting the positive electrode active material particle described herein may be a lithium transition metal oxide having a layered crystal structure capable of reversibly intercalating and deintercalating lithium. Examples of the lithium transition metal oxide having a layered crystal structure include an oxide (nickel-containing lithium composite oxide) containing at least nickel, an oxide containing at least cobalt, and an oxide containing at least manganese as the transition metal.

As a preferable example of the lithium transition metal oxide having a layered crystal structure, a nickel-containing lithium composite oxide containing at least nickel as a constituent element may be mentioned. Such a nickel-containing lithium composite oxide may contain one or more other metal elements other than Li and Ni (that is, a transition metal element other than lithium and nickel and / or a typical metal element). For example, it may be a nickel-containing lithium composite oxide containing nickel, cobalt and manganese as constituent elements. Among these transition metal elements, a nickel-containing lithium composite oxide in which the main component is Ni, or Ni, Co, and Mn are contained in substantially the same ratio is preferable.

In addition to these transition metal elements, one or more other elements may be included as additional constituent elements (addition elements). Examples of such additional elements include Group 1 (alkali metal such as sodium), Group 2 (alkaline earth metals such as magnesium and calcium), Group 4 (transition metals such as titanium and zirconium), Group 6 (chromium, tungsten, etc.) (Transition metal of transition metal), group 8 (transition metal such as iron), group 13 (a metal such as boron or aluminum), and group 17 (halogen such as fluorine) have. As typical examples, W, Zr, Mg, Ca, Na, Fe, Cr, Zn, Si, Sn, Al, B and F are exemplified. Particularly, a compound containing tungsten (W) as an additive element is preferable. By including W as an additive element, it is possible to easily control the above-described half width ratio (A / B) to the preferable range disclosed herein. These additional constituent elements may be added in a proportion of 20 mol% or less, preferably 10 mol% or less of the constituent transition metal elements of nickel, cobalt and manganese.

As a preferable composition of the layered crystal structure lithium transition metal oxide constituting the positive electrode active material particles described herein,

<Formula I>

Li _{1 + x} Ni _y Co _z Mn _{(1- y z )} W _留 M _硫 O ₂

&Lt; RTI ID = 0.0 &gt; LiNiCoMnW < / RTI &gt; In the formula I, M may be one or more elements selected from the group consisting of Zr, Mg, Ca, Na, Fe, Cr, Zn, Si, Sn, Al, have. x may be a real number satisfying 0? x? 0.2. y may be a real number satisfying 0.1 &lt; y &lt; 0.9. z may be a real number satisfying 0.1 &lt; z &lt; 0.4. ? is a real number satisfying 0.0005??? 0.01. In one preferred form, 0.001??? 0.01. ? can be a real number satisfying 0??? 0.01. beta] is substantially 0 (that is, an oxide substantially not containing M). In the chemical formulas representing the lithium transition metal oxide in this specification, although the composition ratio of O (oxygen) is represented as 2 for convenience, it is not strict, and variations in the composition (typically in the range of 1.95 to 2.05) .

<Method for producing lithium transition metal oxide>

Any one of the hollow active material particles disclosed herein may be formed by using, for example, at least one transition metal element contained in the lithium transition metal oxide constituting the active material particle (preferably, a metal element other than lithium contained in the oxide , The transition metal hydroxide is precipitated under appropriate conditions, and the transition metal hydroxide and the lithium compound are mixed and calcined.

Hereinafter, a method for producing a hollow active material particle containing a LiNiCoMnW oxide having a layered crystal structure will be described in detail as an example, with reference to an embodiment of the active material particle producing method, The present invention is not limited thereto. For example, active material particles satisfying the predetermined range of the half-width ratio (A / B) can be produced by using LiNiCoMn oxide without W added thereto. In this case, the respective conditions of Li / M _all , firing temperature and firing time to be described later may be appropriately adjusted so as to satisfy the predetermined range of the half width ratio (A / B).

&Lt; raw material hydroxide production step &

The method for producing an active material particle described herein includes a step of supplying ammonium ion (NH ₄ ⁺ ) to an aqueous solution of a transition metal compound to precipitate particles of a transition metal hydroxide from the aqueous solution (a raw hydroxide producing step) . The solvent (aqueous solvent) constituting the aqueous solution is typically water and may be a mixed solvent mainly composed of water. As a solvent other than the water constituting the mixed solvent, an organic solvent (such as a lower alcohol) which can be mixed with water uniformly is preferable. The aqueous solution of the transition metal compound (hereinafter also referred to as a &quot; transition metal solution &quot;) may be a transition metal element constituting the lithium transition metal oxide (here, Ni, Co, Mn, and W). For example, a transition metal solution containing one or more compounds capable of supplying Ni ions, Co ions, Mn ions and W ions into an aqueous solvent is used. As the metal ion source of Ni, Co and Mn, sulfates, nitrates, chlorides and the like of the above metals can be suitably employed. For example, a transition metal solution of a composition in which nickel sulfate, cobalt sulfate and manganese sulfate are dissolved in an aqueous solvent (preferably water) can be preferably used. As the compound to be a metal ion source of W, for example, sodium tungstate can be preferably used.

The NH ₄ ⁺ may be supplied to the transition metal solution in the form of an aqueous solution (typically an aqueous solution) containing, for example, NH ₄ ⁺ , or may be supplied by blowing ammonia gas directly into the transition metal solution , These feeding methods may be used in combination. An aqueous solution containing NH ₄ ⁺ is, for example, be prepared by dissolving the compound, which may be the original NH ₄ ⁺ (ammonium hydroxide, ammonium nitrate, ammonia gas or the like) in an aqueous solvent. In this embodiment, NH ₄ ⁺ is supplied in the form of an aqueous solution of ammonium hydroxide (that is, ammonia water).

The raw material hydroxide generation process, pH 12 or more (typically pH 12 or more 14 or less, such as pH above 12.2. 13 below), and NH ₄ ⁺ concentration of 25g / L or less (typically from 3 to 25g / L) of And precipitating the transition metal hydroxide from the transition metal solution under the condition (nucleation step). The pH and NH ₄ ⁺ concentration can be adjusted by appropriately balancing the amount of the ammonia water and the amount of the alkaline agent (a compound having an action of causing the liquid to be alkaline). As the alkali agent, for example, sodium hydroxide, potassium hydroxide and the like can be typically used in the form of an aqueous solution. In this embodiment, an aqueous solution of sodium hydroxide is used. In the present specification, the pH value refers to a pH value based on a liquid temperature of 25 占 폚.

The raw hydroxide producing step may further comprise a step of dissolving the nuclei (typically, particulate) of the transition metal hydroxide precipitated in the nucleating step to a pH of less than 12 (typically, pH 10 to less than 12, preferably pH 10 to less than 11.8, (For example, a pH of 11 to 11.8), and a step of growing NH ₄ ⁺ concentration of 1 g / L or more, preferably 3 g / L or more (typically 3 to 25 g / L) have. Generally, it is appropriate to lower the pH of the particle growth step to 0.1 or more (typically 0.3 or more, preferably 0.5 or more, for example, 0.5 to 1.5 or so) with respect to the pH of the nucleation step.

The pH and NH ₄ ⁺ concentration can be adjusted in the same manner as the nucleation step. A particle growth step, by haenghaejim to satisfy the above pH and NH ₄ ⁺ concentration, and preferably, for example, NH ₄ ⁺ than the 15g / L concentration (in the pH 1 to 15g / L, typically from 3 to The transition metal hydroxide (here, Ni, Co, Mn, and W) can be made to fall within the range of 10 g / L to 15 g / L and more preferably 10 g / L or less (for example, 1 to 10 g / L, (That is, a raw hydroxide particle which tends to form a hollow sintered body in which a hole is formed) suitable for forming the hollow active material particle having the hole described therein Can be generated. That is, in the technique disclosed herein, the transition metal hydroxide (here, NiCoMnW (OH)) in the grain growth step is appropriately adjusted by appropriately adjusting the pH of the transition metal solution and the ammonia concentration (ammonium ion concentration) ₂ ) is made faster than the precipitation rate of the transition metal hydroxide (here, NiCoMnW (OH) ₂ ) in the nucleation step. As a result, the density of the vicinity of the outer surface of the transition metal hydroxide particles serving as the precursor is made higher than the internal density of the transition metal hydroxide particles.

The concentration of NH ₄ ⁺ in the grain growing step may be 7 g / L or less (for example, 1 to 7 g / L, more preferably 3 to 7 g / L). The NH ₄ ⁺ concentration in the grain growth step may be, for example, substantially the same as the NH ₄ ⁺ concentration in the nucleation step, or may be lower than the NH ₄ ⁺ concentration in the nucleation step. The rate of precipitation of the transition metal hydroxide can be controlled by adjusting the total number of moles of transition metal ions contained in the liquid phase of the reaction solution (the total molar amount of the transition metal ions included in the transition metal ion supplied to the reaction liquid Concentration) of the sample.

In each of the nucleation step and the particle growth step, the temperature of the reaction solution is preferably controlled to be a substantially constant temperature (for example, a predetermined temperature ± 1 ° C) in a range of approximately 30 ° C to 60 ° C. The temperature of the reaction liquid may be the same in the nucleation step and the particle growth step. Further, it is preferable that the reaction liquid and the atmosphere in the reaction tank are maintained in a non-oxidizing atmosphere through the nucleation step and the particle growth step. The total molar number (total ion concentration) of Ni ions, Co ions and Mn ions contained in the reaction solution can be, for example, about 0.5 to 2.5 mol / L through the nucleation step and the grain growth step, And it is preferably approximately 1.0 to 2.2 mol / L. The molar number (ion concentration) of the W ions contained in the reaction solution can be, for example, about 0.01 to 1.0 mol / L through the nucleation step and the grain growth step. In order to maintain such an ion concentration, the transition metal solution may be supplemented (typically, continuously supplied) in accordance with the precipitation rate of the transition metal hydroxide. The amounts of Ni ions, Co ions, Mn ions, and W ions contained in the reaction solution are preferably set such that the composition of the target active material particles (that is, the molar ratio of Ni, Co, Mn, and W in the LiNiCoMnW oxide constituting the active material particles) It is preferable to use a corresponding amount.

<Addition amount of W>

As described above, the hollow active material particle (LiNiCoMnW oxide) disclosed herein has a half width A of the diffraction peak obtained by the (003) plane in the powder X-ray diffraction pattern using the CuK? Line of the active material particle, (A / B) of the half width B of the diffraction peak obtained by the plane (A) is not more than 0.7. One of preferable conditions for realizing such half width ratio A / B is that the content of tungsten (Addition amount) of the transition metal hydroxide is from 0.05 mol% to 1 mol%, when the total amount of all the transition metal elements (here, Ni, Co and Mn) other than tungsten contained in the transition metal hydroxide is 100 mol% And an ion source are mixed.

Preferably, the W ion source is mixed with another metal ion source such that the content of tungsten is 0.1 mol% to 1 mol% with respect to the total amount of all the transition metal elements. Thus, in the firing step to be described later, the growth of the crystal in the direction orthogonal to the c-axis can be appropriately suppressed, and the active material particles having the half-width ratio (A / B) described above satisfy the predetermined value.

On the other hand, if a large amount of tungsten is added so that the content of tungsten is much larger than 1 mol%, tungsten is excessively segregated at the grain boundaries of the active material, causing an increase in resistance.

<Mixing Process>

In the present embodiment, the transition metal hydroxide particles thus produced (here, complex hydroxide particles containing Ni, Co, Mn and W) are separated from the reaction solution, washed and dried. Then, the transition metal hydroxide particles and the lithium compound are mixed in a desired ratio to prepare an unfavorable mixture (mixing step). In this mixing step, typically, a lithium compound and a lithium compound are mixed in a ratio corresponding to the composition of the target active material particle (that is, the molar ratio of Li, Ni, Co, Mn, and W in the LiNiCoMnW oxide constituting the active material particle) The transition metal hydroxide particles are mixed. As the lithium compound, a lithium compound which can be dissolved by heating and become an oxide, for example, lithium carbonate, lithium hydroxide, or the like can be preferably used.

&Lt; Molar ratio of Li / M _all >

As another preferable condition for realizing the half width ratio (A / B) disclosed here, a mixture of microcrystalline compounds containing a transition metal hydroxide and a lithium compound is mixed with lithium (Li) and a total of all the constituent metal elements ( _Mall ) Is in the range of 1.05 to 1.2 in terms of the molar ratio (Li / M _all ). Preferably, the molar ratio of the sum of lithium (Li) and all the other constituent metal elements (M _all) so as to 1.1≤Li / M _all ≤1.2, is by mixing a lithium compound and a transition metal hydroxide particles with a relatively excessive. As a result, crystal growth in a direction orthogonal to the c-axis can be suppressed when the mixture is calcined, and the active material particles having the above-mentioned half-width ratio (A / B) can satisfy the predetermined value.

On the other hand, to remain in the Li and M _all molar ratio (Li / M _all) is by mixing a lithium compound so as to significantly exceed 1.2 by mass, the excess of lithium component which does not constitute a LiNiCoMnW oxide of a layered crystal structure (alkali components) is active in the Which is undesirable.

&Lt; Firing step &

As described above, the lithium compound and transition metal hydroxide particles are mixed so that Li / _Mall is 1.05 or more, and then the mixture is calcined to obtain active material particles (firing step). This firing step is preferably carried out in an atmosphere richer in oxygen than air or atmosphere. The firing temperature and firing time are one important factor in terms of realizing a predetermined value of the above-mentioned half width ratio (A / B).

<Firing conditions>

Preferably, the maximum firing temperature is determined in the range of 700 DEG C to 1000 DEG C in the oxidizing atmosphere. Thereby, crystal growth in a direction orthogonal to the c-axis at the time of sintering is suppressed, and active material particles satisfying the above-mentioned half width ratio (A / B) of 0.7 or less can be produced. It is preferable that the maximum firing temperature is set to be 800 DEG C or higher (preferably 850 DEG C to 1000 DEG C, for example, 850 DEG C to 950 DEG C). According to the maximum firing temperature in this range, active material particles satisfying the above-mentioned half width ratio (A / B) of 0.45 or more and 0.7 or less can be produced. The firing time (firing time at the maximum firing temperature) may be generally from 3 hours to 20 hours (preferably from 5 hours to 20 hours, particularly preferably from 10 hours to 20 hours). When the sintering time is too long, the crystal grows excessively at the time of sintering, so that the half width ratio (A / B) described above may exceed 0.7. On the other hand, if the sintering time is too short, The above-mentioned half width ratio (A / B) may be less than 0.45.

In a preferred form, the mixture is heated at a temperature T1 of 700 ° C or higher and 900 ° C or lower (i.e. 700 ° C? T 1? 900 ° C, for example 700 ° C? T 1? 800 ° C, typically 700 ° C? Firing the resulting product through the first firing step at a temperature T2 of 800 ° C or more and 1000 ° C or less (i.e., 800 ° C? T2? 1000 ° C, for example, 850 ° C? And a second firing step. By firing the mixture by such a multistage firing schedule, it is possible to more efficiently form the hollow active material particles in which the half width ratio (A / B) is a predetermined value. It is preferable that T1 and T2 are set so that T1 < T2.

The first sintering step and the second sintering step may be performed continuously (for example, even after the mixture is maintained at the first sintering temperature T1 and subsequently heated to the second sintering temperature T2 and maintained at the temperature T2) , Or may be maintained at the first firing temperature T1 and then once cooled (for example, to a room temperature), and subjected to crushing and sieving if necessary, and then provided to the second firing step.

Further, in the technique described here, the first firing step is a step of firing at a temperature T1 lower than the melting point, which is lower than the temperature of the second firing step, as the sintering reaction of the target lithium transition metal oxide proceeds . The second firing step can be understood as a step of firing at a temperature T2 lower than the melting point and higher than the first firing step as the sintering reaction of the target lithium transition metal oxide proceeds. It is preferable to set a temperature difference between T1 and T2 of 50 DEG C or higher (typically 100 DEG C or higher, for example, 150 DEG C or higher).

The lithium transition metal oxide (LiNiCoMnW oxide) obtained by the above-described firing step is preferably pulverized by cooling, milling, or the like, and then classified to obtain active material particles. Here, the particles of the transition metal hydroxide, which is a precursor of the positive electrode active material particles, have a small inner density and a large density near the outer surface. Thus, in the sintering step, sintering is performed such that the inside of the particles of the transition metal hydroxide, which is a precursor, having a small density is introduced into the vicinity of the outer surface having high density and high mechanical strength. As a result, the shell portion 15 of the positive electrode active material particle 10 is formed and the hollow portion 16 is formed. Further, when the crystal grows during sintering, a through hole 18 is formed in a part of the shell 15 through the shell 15. Thereby, as shown in Fig. 1, the shell portion 15, the hollow portion 16, and the positive electrode active material particle 10 having the through hole 18 are formed.

Such a positive electrode active material particle 10 is a preferred embodiment, and the BET specific surface area of the above-described active material particle 10 can be set to about 0.5 m 2 / g to 1.9 m 2 / g. The BET specific surface area of the active material particles 10 may be more preferably about 0.6 m2 / g or more, and more preferably about 0.8 m2 / g or more. The BET specific surface area of the active material particles 10 may be, for example, about 1.7 m 2 / g or less, and more preferably about 1.5 m 2 / g or less.

In addition, the active material particles 10 are harder and more stable in shape than the active material particles 10 (for example, a spray-firing method (also referred to as a spray-drying method)). The active material particles 10 have an average hardness of 0.5 MPa or more in a dynamic hardness measurement using, for example, a planar diamond indenter having a diameter of 50 탆 and under a condition of a load speed of 0.5 mN / sec to 3 mN / sec. Here, the average hardness is a value obtained by dynamic hardness measurement using a planar diamond indenter having a diameter of 50 mu m under a condition of a load speed of 0.5 mN / sec to 3 mN / sec. As described above, the active material particles having a hollow structure and a high average hardness (in other words, having a high shape-retaining ability) can provide a battery that stably exhibits higher performance. As a result, for example, a lithium secondary battery having a low internal resistance (in other words, a good output characteristic) and a low rise in resistance even in a charge / discharge cycle (particularly, a charge / discharge cycle including discharging at a high rate) Can also contribute to building.

In the production of such active material particles 10, in particular, the transition metal solution may contain nickel. When the transition metal solution contains nickel, when transition metal hydroxide precipitates in the nucleation step and the grain growth step, particles of transition metal hydroxide are produced in the form of secondary particles in which a plurality of minute primary particles are gathered do. In addition, in the temperature range during firing, crystals grow while maintaining the shape of primary particles of such transition metal hydroxide. In addition, when the transition metal solution does not contain nickel at all and contains cobalt and particles of lithium cobalt oxide (LiCoO ₂ ) are produced by firing, the shape of the primary particles can not be maintained, Is sintered. As a result, it is difficult to obtain the active material particles 10 (see Fig. 1) having the hollow portion 16 as described above.

In the technique disclosed herein, as described above, in the powder X-ray diffraction pattern using the CuK? Ray, the ratio (A) of the half width A of the (003) diffraction surface peak to the half width B / B) of 0.7 or less is used as the positive electrode active material. Therefore, except for using the positive electrode active material particles described above, a lithium secondary battery can be constructed by employing the same materials and processes as those of the conventional art.

For example, carbon black such as acetylene black (AB), ketjen black or the like, powdery carbon material such as graphite or the like may be mixed with the positive electrode active material particle described herein as a conductive material. A binder such as polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR), polytetrafluoroethylene (PTFE), and carboxymethyl cellulose (CMC) may be added in addition to the positive electrode active material and the conductive material have. They may be dispersed in an appropriate dispersion medium and kneaded to prepare a composition for forming a positive electrode active material layer. The positive electrode for a lithium secondary battery can be produced by applying the composition in an appropriate amount onto a positive electrode current collector made of aluminum or an alloy mainly composed of aluminum, followed by drying and pressing.

On the other hand, a negative electrode for a lithium secondary battery, which serves as a counter electrode, can be manufactured by the same method as the conventional one. For example, the negative electrode active material may be a material capable of releasing lithium ions while occluding the lithium ions. As a typical example, a powdered carbon material including graphite (graphite) and the like can be given. Particularly, since graphite particles are small in particle size and have a large surface area per unit volume, they can be made into a negative electrode active material suitable for rapid charge / discharge (for example, high output discharge).

The paste-like composition for forming the negative electrode active material layer can be prepared by dispersing and kneading such powdery material together with an appropriate binder (binder) in a suitable dispersion medium, like the positive electrode. The negative electrode for a lithium secondary battery can be produced by drying and pressing the composition while applying an appropriate amount to a negative electrode current collector made of copper or nickel or an alloy thereof, preferably.

In the lithium secondary battery using the lithium transition metal oxide described above as a positive electrode active material, a separator similar to the conventional one can be used. For example, a porous sheet (porous film) containing a polyolefin resin or the like can be used.

As the electrolyte, there can be used the same non-aqueous electrolyte (typically, an electrolyte) conventionally used in a lithium secondary battery, without particular limitation. Typically, it is a composition comprising a support salt in a suitable non-aqueous solvent. Examples of the non-aqueous solvent include propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate May be used alone or in combination of two or more. Examples of the support salt include LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiI, and the like can be used.

There is no particular limitation on the shape (external shape and size) of the lithium secondary battery to be constructed as long as a configuration using the lithium transition metal oxide as the positive electrode active material is adopted. The battery case may have a cylindrical shape or a rectangular parallelepiped shape, or may be a small button shape.

Hereinafter, the use of the positive electrode active material described here will be described as an example of a lithium secondary battery having a wound electrode body, but the configuration of the present invention is not intended to be limited to these embodiments.

3, the rechargeable lithium battery 100 according to the present embodiment has a structure in which the elongated positive electrode sheet 30 and the elongated negative electrode sheet 20 are flatly formed via the elongated separator 40 A configuration in which a wound electrode member 80 (wound electrode body) is accommodated in a container 50 having a shape (flat box-like shape) capable of accommodating the wound electrode body 80 together with a nonaqueous electrolytic solution .

The container 50 includes a flat rectangular parallelepiped container body 52 with an opened upper end and a lid 54 covering the opening. As a material constituting the container 50, a metal material such as aluminum or steel is preferably used (aluminum in this embodiment). Alternatively, it may be a container 50 formed by molding a resin material such as polyphenylene sulfide resin (PPS) or polyimide resin. The positive electrode terminal 70 electrically connected to the positive electrode of the wound electrode body 80 and the positive electrode terminal 70 electrically connected to the negative electrode 20 of the electrode body 80 are formed on the upper surface (i.e., the lid 54) And a negative electrode terminal 72 is provided. Inside the container 50, a flat-shaped wound electrode body 80 is accommodated together with a non-aqueous electrolyte (not shown).

The material constituting the wound electrode body 80 of the above constitution and the member itself may be the same as the electrode body of the conventional lithium secondary battery except that the lithium transition metal oxide obtained by the method of this embodiment is used as the positive electrode active material , There is no particular limitation. As shown in Fig. 4, the wound electrode body 80 according to the present embodiment has a long (band-shaped) sheet structure at the previous stage of assembling the wound electrode body 80. Fig.

The positive electrode sheet 30 has a structure in which a positive electrode active material layer 34 including a positive electrode active material is held on both surfaces of a long sheet-like positive electrode current collector 32. The positive electrode active material layer 34 is not attached to one widthwise side edge portion (upper side edge portion in FIG. 4) of the positive electrode sheet 30, but the positive electrode current collector 32 is exposed with a constant width A positive electrode active material layer nonformed portion is formed. The negative electrode sheet 20 also has a structure in which a negative electrode active material layer 24 including a negative electrode active material is held on both surfaces of a long thin sheet-like negative electrode current collector 22 similarly to the positive electrode sheet 30. However, the negative electrode active material layer 24 is not attached to one widthwise side edge portion (the lower side edge portion in FIG. 4) of the negative electrode sheet 20, and the negative electrode current collector 22 is exposed with a constant width And a negative electrode active material layer nonformed portion is formed.

In producing the wound electrode body 80, the positive electrode sheet 30 and the negative electrode sheet 20 are stacked with the separator 40 interposed therebetween. At this time, the positive electrode sheet 30 and the positive electrode sheet 30 are stacked so that the positive electrode active material layer non-forming portion of the positive electrode sheet 30 and the negative electrode active material layer non-forming portion of the negative electrode sheet 20 are respectively emptied from both sides in the width direction of the separator 40 The negative electrode sheet 20 is laminated so as to be slightly shifted in the width direction. The laminated laminate thus formed is wound, and then the obtained winding body is crushed from the side direction so that the flat wound electrode body 80 can be manufactured.

The wound core portion 82 (that is, the positive electrode active material layer 34 of the positive electrode sheet 30 and the negative electrode active material layer 24 of the negative electrode sheet 20) is formed in the center portion of the wound electrode body 80 in the direction of the winding axis. And the separator 40 are stacked in this order). The electrode active material layer non-forming portions of the positive electrode sheet 30 and the negative electrode sheet 20 are respectively outwardly projected from the winding core portions 82 at both ends in the winding axis direction of the wound electrode body 80. The positive electrode lead terminal 84 (that is, the non-forming portion of the positive electrode active material layer 34) and the negative electrode side vacant portion 86 (that is, the non-forming portion of the negative electrode active material layer 24) 74 and a negative electrode lead terminal 76 are respectively provided and are electrically connected to the above-described positive electrode terminal 70 and negative electrode terminal 72, respectively.

The wound electrode body 80 having such a configuration is housed in the container body 52 and an appropriate nonaqueous electrolyte solution 90 is placed in the container body 52 to be impregnated in the wound electrode body 80. The assembly of the lithium secondary battery 100 according to the present embodiment is completed by sealing the opening of the container body 52 by welding with the lid 54 or the like. The sealing process of the container main body 52 and the process of disposing the electrolyte (ingot) can be performed in the same manner as in the conventional method for manufacturing a lithium secondary battery. Thereafter, conditioning (initial charging and discharging) of the battery is performed. The process such as gas discharge and quality inspection may be performed as necessary.

In the following test examples, a lithium secondary battery for test was constructed using the positive electrode active material particles described herein, and the performance thereof was evaluated.

(Test Example 1)

&Lt; Production of Active Material Particles Having Hollow Structure (Samples 1 to 16)

In a reaction vessel provided and set to a temperature within 40 ℃ tank the overflow pipe, into the ion-exchanged water, stirring by flowing nitrogen gas, the ion-nitrogen substitution box and the reactor oxygen gas with the exchange (O ₂₎ concentration And adjusted to a non-oxidizing atmosphere of 2.0%. Subsequently, 25% sodium hydroxide aqueous solution and 25% ammonia water were added so that the pH measured at 25 ° C was 12.0 and the NH ₄ ⁺ concentration in the solution was 15 g / L.

Nickel sulfate, cobalt sulfate and manganese sulfate were dissolved in water such that the molar ratio of Ni: Co: Mn was 0.33: 0.33: 0.33 and the total molar concentration of these metal elements was 1.8 mol / L, . Further, sodium tungstate was dissolved in water so that the molar concentration of the tungsten element was 0.05 mol / L to prepare a mixed aqueous solution W2. By supplying a mixed aqueous solution W1 and the mixed aqueous solution W2 with 25% NaOH aqueous solution and 25% aqueous ammonia at a constant rate into the reaction tank, while controlling the reaction solution was pH 12.5, NH ₄ ⁺ concentration 5g / L, NiCoMnW compound from the reaction solution The hydroxide was crystallized (nucleation step). In Sample 1, the content (tungsten content) of tungsten contained in the reaction solution was 100 mol% in terms of mole percentage of the total of all the transition metal elements (here, Ni, Co and Mn) other than tungsten in the reaction solution , It was adjusted to 0.5 mol%.

The supply of the aqueous 25% NaOH solution was stopped at a portion where 2 minutes and 30 seconds elapsed from the start of the supply of the mixed aqueous solution. The mixed aqueous solution and 25% ammonia water were continuously supplied at a constant rate. After the pH of the reaction solution had dropped to 11.6, the supply of aqueous 25% NaOH solution was resumed. Then, the operation of supplying the mixed aqueous solution, 25% NaOH aqueous solution, and 25% ammonia water was continued for 4 hours while controlling the reaction solution to pH 11.6 and NH ₄ ⁺ concentration of 5 g / L to grow NiCoMnW complex hydroxide particles step). Thereafter, the product was taken out of the reaction tank, washed with water and dried. In this _{manner, Ni 0 .33 Co 0 .33 Mn} 0 .33 W 0 .005 (OH) 2 + α ( where α expression in the 0≤α≤0.5 Im) to obtain a complex hydroxide particles of the composition expressed in .

The complex hydroxide particles were subjected to a heat treatment at 150 캜 for 12 hours in an air atmosphere. Li ₂ CO ₃ as the lithium source and the composite hydroxide particle were then mixed with the lithium hydroxide in the ratio of the molar number (Li) of lithium to the total molar number (M _all ) of Ni, Co, Mn and W constituting the complex hydroxide (Li / M _all ratio) was about 1.15. This mixture was calcined at 760 ° C for 4 hours and then calcined at 950 ° C (maximum calcination temperature) for 20 hours. Thereafter, the fired product was pulverized and sieved. Thus, an active material particle sample having a composition represented by Li _{1 .15} Ni _{0 .33} Co _{0 .33} Mn _{0 .33} W _{0 .005} O ₂ was obtained.

More specifically, by adjusting the conditions of the W addition amount and the maximum firing temperature in the process of fabricating the above-described active material particle sample, the W addition amount is made different between 0 mol% and 0.7 mol%, and the maximum firing temperature is 750 Deg.] C to 1000 [deg.] C, thereby producing active material particles of Samples 1 to 16 shown in Table 1. [ These active material particle samples were subjected to surface SEM observation. As a result, it was confirmed that, in either active material particle sample, several through holes were formed in the secondary particles in which a plurality of primary particles were aggregated.

The powder X-ray diffraction patterns of the samples of the active material particles of Samples 1 to 16 were measured by the above method and the half width A of the peak obtained by the diffraction surface of the Miller index (003) and the diffraction surface of the Miller index 104 The ratio (A / B) of the half width B of the obtained peak was found to be in the range of 0.38 to 1.12. The obtained active material particle samples were sieved to adjust the average particle diameter (median diameter D50) to about 3 to 8 mu m and the specific surface area to about 0.5 to 1.9 m2 / g.

&Lt; Production of active material particles having a solid structure (Samples 17 to 21)

In a reaction vessel provided and set to a temperature within 40 ℃ tank the overflow pipe, into the ion-exchanged water, stirring by flowing nitrogen gas, the ion-nitrogen substitution box and the reactor oxygen gas with the exchange (O ₂₎ concentration And adjusted to a non-oxidizing atmosphere of 2.0%. Subsequently, a 25% aqueous solution of sodium hydroxide and a 25% aqueous ammonia were added so that the pH measured at 25 ° C was 12.0 and the concentration of NH ₄ ^{+ in the} solution was 15 g / L.

Nickel sulfate, cobalt sulfate and manganese sulfate were dissolved in water such that the molar ratio of Ni: Co: Mn was 0.33: 0.33: 0.33 and the total molar concentration of these metal elements was 1.8 mol / L, Respectively. Further, sodium tungstate was dissolved in water so that the molar concentration of the tungsten element was 0.05 mol / L to prepare a mixed aqueous solution W2. The mixed aqueous solution W1, the mixed aqueous solution W2, the 25% NaOH aqueous solution and the 25% ammonia water were fed into the reaction tank at a constant rate such that the average residence time of the NiCoMnW complex hydroxide particles precipitated in the reaction tank became 10 hours, Was controlled to have a pH of 12.0 and an NH ₄ ⁺ concentration of 15 g / L to continuously crystallize the NiCoMnW complex hydroxide (product) continuously from the overflow pipe after the reaction tank had reached a steady state, washed with water and dried . In this _{manner, Ni 0 .33 Co 0 .33 Mn} 0 .33 W 0 .005 (OH) 2 + α ( where α expression in the 0≤α≤0.5 Im) to obtain a complex hydroxide particles of the composition expressed in .

The complex hydroxide particles were subjected to a heat treatment at 150 캜 for 12 hours in an air atmosphere. Li ₂ CO ₃ as a lithium source and the complex hydroxide particle are mixed in a ratio of the molar number of lithium (Li) to the total molar number (M _all ) of Ni, Co, Mn and W constituting the complex hydroxide (Li: M _all ) was 1.15: 1. This mixture was calcined at 760 占 폚 for 4 hours and then calcined at 980 占 폚 for 20 hours. Thereafter, the fired product was pulverized and sieved. Thus, an active material particle sample having a composition represented by Li _{1 .15} Ni _{0 .33} Co _{0 .33} Mn _{0 .33} W _{0 .005} O ₂ was obtained.

Active material particles of Samples 17 to 21 shown in Table 1 were prepared by controlling the conditions of the W addition amount and the maximum firing temperature in the above-mentioned process of producing the active material particle sample. The appearance of these samples was observed by the scanning electron microscope. As a result, it was confirmed that the sample was compact in both samples. The powder X-ray diffraction patterns of these active material particle samples were measured by the above method and the peak width A of the peak obtained by the diffraction surface of the Miller index (003) and the peak A obtained by the diffraction surface of the Miller index 104 (A / B) of the full width at half maximum (B) to the full width at half maximum (B) was found to be in the range of 0.42 to 0.85.

A lithium secondary battery for test was constructed using the active material particle samples of Samples 1 to 21, and the performance thereof was evaluated. Here, a plurality of samples of lithium secondary batteries for test, which are different from each other only in the positive electrode active material particles, were constructed and their performance was compared.

<Positive electrode sheet>

The active material particle sample thus obtained, AB (conductive material), and PVDF (binder) were mixed with N-methylpyrrolidone (NMP) so that the mass ratio of these materials was 90: 8: 2, Lt; / RTI &gt; The composition for forming the positive electrode active material layer was applied on both sides of a long-shaped aluminum foil (positive electrode collector) having a thickness of 15 mu m and dried to prepare a positive electrode sheet in which a positive electrode active material layer was formed on both surfaces of the positive electrode collector. The application amount of the composition for the positive electrode active material layer was adjusted to be about 11.8 mg / cm 2 (on a solid basis) on both sides. After drying, the positive electrode active material layer was pressed to have a density of about 2.3 g / cm 3.

&Lt;

Natural graphite powder as the negative electrode active material, SBR and CMC were dispersed in water such that the mass ratio of these materials was 98.6: 0.7: 0.7, thereby preparing a composition for forming the negative electrode active material layer. The composition for forming the negative electrode active material layer was applied on both sides of a long copper foil (negative electrode collector) having a thickness of 10 mu m and dried to prepare a negative electrode sheet having negative electrode active material layers on both surfaces of the negative electrode collector. The coating amount of the composition for the negative electrode active material layer was adjusted to be about 7.5 mg / cm 2 (on a solid basis) on both sides. After drying, the negative electrode active material layer was pressed to have a density of about 1.0 g / cm 3 to 1.4 g / cm 3.

<Lithium secondary battery>

The positive electrode sheet and the negative electrode sheet were laminated and wound with two separators (using a single-layered structure made of porous polyethylene) therebetween, and the wound body was squashed from the side direction to make a flat wound electrode body. The wound electrode body was housed in a box-shaped battery container together with the nonaqueous electrolyte solution, and the opening of the battery container was hermetically sealed. As the non-aqueous electrolyte, a mixed solvent containing EC, EMC, and DMC in a volume ratio of 3: 3: 4 was used and LiPF ₆ as a supporting salt was contained at a concentration of about 1 mol / liter. An electrolytic solution obtained by dissolving a mixture of a difluorophosphate (LiPO ₂ F ₂ ) and lithium bisoxalate borate (LiBOB) in a ratio of about 0.05 mol / L may be optionally used. Thus, the lithium secondary battery was assembled. Thereafter, an initial charging / discharging treatment (conditioning) was performed by a normal method to obtain a lithium rechargeable battery for testing. In this test battery, the opposing capacity ratio calculated from the charging capacity of the positive electrode and the charging capacity of the negative electrode is adjusted to 1.5 to 1.9.

&Lt; Measurement of rated capacity (initial capacity) >

Next, the rated capacity of the test lithium secondary battery constructed as described above was measured at a temperature of 25 캜 in a voltage range of 3.0 V to 4.1 V by the following steps 1 to 3.

Procedure 1: Discharge to 3.0 V with a constant current of 1C, discharge to constant voltage for 2 hours, and stop for 10 seconds.

Procedure 2: Charge to 4.1 V with a constant current of 1 C, continue charging for 2.5 hours at constant voltage, and stop for 10 seconds.

Procedure 3: Discharge to 3.0 V with a constant current of 0.5 C, discharge to constant voltage for 2 hours, and stop for 10 seconds.

The discharge capacity (CCCV discharge capacity) in the discharge from the constant current discharge to the constant voltage discharge in the procedure 3 was defined as the rated capacity (initial capacity). In this test lithium secondary battery, the rated capacity was approximately 4 Ah.

<SOC adjustment>

The SOC of each test lithium secondary battery was adjusted by the procedures of the following 1 and 2. In addition, SOC adjustment was carried out under a temperature environment of 25 캜 so as to make the influence by the temperature constant.

Procedure 1: The battery is charged at a constant current of 3 V to 1 C to provide a charged state (SOC 60%) of approximately 60% of the rated capacity. Here, &quot; SOC &quot; means the State of Charge.

Procedure 2: After the procedure 1, charge at a constant voltage for 2.5 hours.

Thereby, the test lithium secondary battery can be adjusted to a predetermined charged state.

<Output characteristics at -30 ° C and SOC 27% charge>

The output characteristics of each of the test lithium secondary batteries in a charged state of -30 캜 and an SOC of 27% were measured. The output characteristics were measured by the following procedure.

Procedure 1: The SOC is adjusted to 27% by a constant current charge of 3.0 V to 1 C in a temperature environment of room temperature (here, 25 캜), and the battery is charged for one hour at a constant voltage.

Procedure 2: The battery adjusted to 27% of the SOC is allowed to stand in a thermostatic chamber at -30 캜 for 6 hours.

Procedure 3: After the procedure 2, discharge is carried out at a temperature of -30 ° C from SOC 27% to a constant wattage (W). At this time, the number of seconds from the start of discharge until the voltage becomes 2.0 V is measured.

Procedure 4: The above steps 1 to 3 are repeated while changing the normal discharge voltage in the procedure 3 from 80W to 200W. Here, the positive wattage discharge voltage of the procedure 3 is set to 80 W for the first time, 90 W for the second time, 100 W for the third time, The above steps 1 to 3 are repeated until the positive discharge voltage of the process 3 becomes 200 W while increasing the positive discharge voltage by 10 W. [

Step 5: The horizontal axis represents the number of seconds up to 2.0 V measured under the condition of the constant wattage in the above procedure 4, and the W at 2 seconds is calculated as the output characteristic from the approximate curve of the plot obtained by taking the W as the vertical axis at that time.

Such an output characteristic shows an output capable of exerting a test lithium secondary battery even when it is left in an environment of an extremely low temperature of -30 DEG C for a predetermined time, which is a low charge amount of about SOC 27%. As a result, the above output characteristic shows that the higher the value of W, the higher the output can be stably obtained even in the low SOC state. The results are shown in Table 1 and FIG. 5 is a graph showing the relationship between the half width ratio (A / B) and the output characteristic (W).

As shown in Table 1 and FIG. 5, the output characteristics were improved as the half width ratio (A / B) was small, even when the active material particles had a hollow portion and no hollow portion. However, when the active material particle had a hollow portion, the rate of increase (slope) of the output with respect to the change of the half width ratio (A / B) was larger than when there was no hollow portion. Particularly, in the region where the half width ratio (A / B) was 0.7 or less, a very high output value of 110 W or more was obtained by providing a hollow portion in the active material particles. In view of this, in terms of improvement of the output in the low SOC region by defining the above half-width ratio (A / B) in the preferable range described herein, the hollow structure active material particles ) Was used, it was confirmed to be particularly effective. From the viewpoint of improving the output characteristics in the low SOC region, it is appropriate to provide a hollow portion in the active material particle and to set the half width ratio (A / B) to 0.7 or less, preferably 0.6 or less (Samples 1 to 8 ), More preferably not more than 0.5 (samples 1 to 4), particularly preferably not more than 0.4 (sample 1).

<High temperature preservation durability>

The capacity retention ratio after each of the test lithium secondary batteries was stored at 60 占 폚 in a SOC 80% charged state was measured. The measurement was carried out in the following procedure.

Procedure 1: The SOC was adjusted to 80% by a constant current charge of 1 C in a temperature environment of room temperature (here, 25 캜), and then charged for 2.5 hours at a constant voltage.

Procedure 2: The cell adjusted to the SOC of 80% was put in a thermostatic chamber at 60 캜 and stored for 60 days.

Procedure 3: After the procedure 2, the capacity was measured in the same manner as the above-mentioned "measurement of the rated capacity (initial capacity)", and the capacity was obtained after storing at 60 ° C. The capacity retention ratio (%) after storage at 60 占 폚 was calculated by the following formula: [(capacity after storage at 60 占 폚 / initial capacity) 占 100]. The results are shown in Table 1 and Fig. 6 is a graph showing the relationship between the half width ratio (A / B) and the capacity retention ratio (%) after storage at 60 캜 for a cell using the hollow structure active material particles of Samples 1 to 16.

As shown in Table 1 and FIG. 6, according to the battery using the active material particles of Samples 1 to 12 having the half width ratio (A / B) of 0.48 to 0.71, the capacity in the high temperature storage test stored at 60 占 폚 for 60 days All of the retention ratios were 90% or more and excellent durability performance was shown. On the other hand, in the battery using the active material particles of Samples 1 to 3 having a half width ratio (A / B) of 0.43 or less, the capacity retention rate in the high temperature preservation test was less than 90% and the durability was insufficient. Further, all of the batteries of Samples 13 to 16 having a half width ratio (A / B) of 0.78 or more had capacity retention ratios of less than 90%. In this respect, from the viewpoint of improving the high-temperature storage durability performance, the half width ratio (A / B) is suitably from 0.45 to 0.75 (samples 4 to 12), preferably from 0.5 to 0.70 (samples 5 to 11). (A / B) is suitable from 0.45 to 0.7 (Samples 4 to 11), preferably from 0.45 to 0.60 (Samples 4 to 8) from the viewpoint of satisfying both of the output characteristics and the high-temperature storage durability performance. .

In order to confirm the effect of the production conditions (maximum firing temperature, firing time, W addition amount, Li / M _all ratio) on the half width ratio (A / B) when the active material particles having a hollow structure were produced, Test was carried out.

(Test Example 2)

In this example, in the process of fabricating active material particles of the hollow structure of Samples 1 to 16 described above, active material particles were produced by differentiating the maximum firing temperature from 700 to 1000 占 폚. The firing time was 20 hours, the addition amount of W was 0.5 mol%, and the Li / M _all ratio was 1.15. The powder X-ray diffraction pattern of the obtained active material particle sample was measured by the aforementioned method and the half width A of the peak obtained by the diffraction surface of the Miller index (003) and the half value of the peak obtained by the diffraction surface of the Miller index 104 (A / B) of the width B was calculated. The results are shown in Fig. 7 is a graph showing the relationship between the maximum firing temperature and the half width ratio (A / B).

As apparent from Fig. 7, the half width ratio (A / B) showed a tendency to decrease as the maximum firing temperature decreased. In the case of the active material particle sample disclosed herein, it is preferable to set the maximum firing temperature to 850 캜 to 950 캜 in order to set the half width ratio (A / B) to 0.45 to 0.7.

(Test Example 3)

In this example, in the process of fabricating active material particles of the hollow structure of Samples 1 to 16 described above, active material particles were produced by varying the sintering time (sintering time at the maximum sintering temperature from 3 to 20 hours) the sintering temperature is 950 ℃, W amount is 0.5 mol%, Li / M _all ratio was constant at 1.15. the powder X-ray diffraction pattern of the resulting active material particle sample was measured by the method described above, the diffraction of the Miller index (003) The ratio (A / B) of the half width A of the peak obtained by the plane and the half width B of the peak obtained by the diffractive surface of the Miller index 104 was calculated. The results are shown in Fig. Is a graph showing the relationship between the firing time and the half width ratio (A / B).

As evident from Fig. 8, the half width ratio (A / B) showed a tendency to decrease with decreasing firing time. In the case of the active material particle sample disclosed here, in order to set the half width ratio (A / B) to 0.45 to 0.7, the baking time is preferably 20 hours or less.

(Test Example 4)

In this example, active material particles were prepared by varying the amount of W added between 0 and 1 mol% in the process of fabricating active material particles of the hollow structure of Samples 1 to 16 described above. The maximum firing temperature was 950 ° C, the firing time was 20 hours, and the Li / M _all ratio was 1.15. The powder X-ray diffraction pattern of the obtained active material particle sample was measured by the aforementioned method and the half width A of the peak obtained by the diffraction surface of the Miller index (003) and the half value of the peak obtained by the diffraction surface of the Miller index 104 (A / B) of the width B was calculated. The results are shown in Fig. 9 is a graph showing the relationship between the amount of addition of W and the half width ratio (A / B).

As is apparent from Fig. 9, it was confirmed that the addition of W significantly reduced the half width ratio (A / B). In addition, as the amount of W added was increased, the half width ratio (A / B) showed a tendency to decrease. In the case of the active material particle sample disclosed herein, it is preferable to set the amount of W to be added in the range of 0.05 mol% to 1 mol% in order to set the half width ratio (A / B) to 0.45 to 0.7.

(Test Example 5)

In this example, active material particles were prepared by varying the Li / _Mall ratio between 1.05 and 1.1 in the process of fabricating active material particles of the hollow structure of Samples 1 to 16 described above. The maximum firing temperature was 950 ° C., the firing time was 20 hours, and the amount of W added was kept constant at 0.5 mol%. The powder X-ray diffraction pattern of the obtained active material particle sample was measured by the aforementioned method and the half width A of the peak obtained by the diffraction surface of the Miller index (003) and the half value of the peak obtained by the diffraction surface of the Miller index 104 (A / B) of the width B was calculated. The results are shown in Fig. 10 is a graph showing the relationship between Li / _Mall ratio and half width ratio (A / B).

As apparent from Fig. 10, the half width ratio (A / B) showed a tendency to decrease as the Li / _Mall ratio was increased. In the case of the active material particle sample disclosed herein, it is preferable that the Li / _Mall ratio is 1.05 or more in order to set the half width ratio (A / B) to 0.45 to 0.7.

While the present invention has been described in detail, the foregoing embodiments are merely illustrative, and the invention disclosed herein includes various modifications and variations of the above-described specific examples.

The lithium secondary battery provided by the technique disclosed herein can be used as a lithium secondary battery suitable for various applications in that it exhibits excellent performance as described above. For example, it can be preferably used as a power source for a motor (electric motor) mounted on a vehicle such as an automobile. Such a lithium secondary battery may be used in the form of a battery composed of a plurality of such batteries connected in series and / or in parallel. Therefore, according to the technique disclosed in this specification, as schematically shown in Fig. 11, a vehicle 1 (typically, an automobile, particularly a vehicle) having such a lithium secondary battery 100 (which may be in the form of a battery) A hybrid vehicle, an electric vehicle, or a motor vehicle having an electric motor such as a fuel cell vehicle) may be provided.

According to the present invention, it is possible to provide a lithium secondary battery capable of stably exhibiting a high output even in a low SOC region.

Claims (12)

The whole house,
An active material layer containing active material particles held on the current collector,
And,
Wherein the active material particles constitute a hollow structure having a hollow portion formed inside the secondary particle and a shell portion surrounding the hollow portion, the secondary particle comprising a plurality of primary particles of a lithium transition metal oxide,
The secondary particle has a through hole penetrating from the outside to the hollow portion,
When the ratio (A / B) of the half width A of the diffraction peak obtained by the (003) plane to the half width B of the diffraction peak obtained by the (104) plane in the powder X-ray diffraction pattern of the active material particle is (A / B) &lt; / = 0.7. The method according to claim 1,
Wherein said half width ratio (A / B) satisfies the following formula: 0.45? (A / B)? 0.7. 3. The method according to claim 1 or 2,
Wherein an average thickness of the shell portion surrounding the hollow portion of the active material particles is 0.1 占 퐉 to 2.2 占 퐉. 4. The method according to any one of claims 1 to 3,
Wherein the lithium transition metal oxide is a compound having a layered crystal structure containing at least nickel as a constituent element. 5. The method according to any one of claims 1 to 4,
The lithium transition metal oxide is a compound of a layered crystal structure containing tungsten,
Wherein the content of tungsten is from 0.05 mol% to 1 mol% when the sum of all the transition metal elements other than tungsten in the compound is 100 mol% in terms of a mole percentage. 6. The method according to any one of claims 1 to 5,
The lithium transition metal oxide may be represented by the following general formula:
<Formula 1>
Li _{1 + x} Ni _y Co _z Mn _{(1- y z )} W _留 M _硫 O ₂
(X, y, z,? And? In the formula (1)
0? X? 0.2,
0.1 < y < 0.9,
0.1 < z < 0.4,
0.0005??? 0.01,
0.0 &lt; / = 0.0 &lt; / = 0.01,
M is not present or is one or more elements selected from the group consisting of Zr, Mg, Ca, Na, Fe, Cr, Zn, Si, Sn, Al,
Wherein the lithium secondary battery is a compound having a layered crystal structure represented by the following formula. 7. The method according to any one of claims 1 to 6,
The active-
A raw hydroxide producing step of supplying ammonium ions to an aqueous solution of a transition metal compound to precipitate transition metal hydroxide particles from the aqueous solution, wherein the aqueous solution is at least one of transition metal elements constituting the lithium transition metal oxide 1;
A mixing step of mixing the transition metal hydroxide and a lithium compound to prepare an unflavored mixture; And
A firing step of firing the mixture to obtain the active material particles;
Wherein the active material particles are prepared by a manufacturing method comprising a lithium secondary battery. A secondary particle having a plurality of primary particles of a lithium-transition metal oxide, the secondary particle having a hollow portion formed inside the secondary particle and a shell portion surrounding the hollow portion, the secondary particle penetrating from the outside to the hollow portion And a through hole is formed in the through hole, the method comprising the steps of:
A raw hydroxide producing step of supplying ammonium ions to an aqueous solution of a transition metal compound to precipitate particles of a transition metal hydroxide from the aqueous solution, wherein the aqueous solution contains at least a transition metal element constituting the lithium transition metal oxide One containing;
A fine mixture castle that said transition comprises a metal hydroxide and a lithium compound, the lithium excess to the range of the molar ratio (Li / M _all) of 1.05 to 1.2 of a total amount of lithium (Li) and all the other constituent metal elements (M _all) A manufacturing process; And
Calcining the mixture at a temperature in the range of 700 ° C to 1000 ° C to obtain the active material particles;
/ RTI &gt;
(A / B) of the half width A of the diffraction peak obtained by the (003) plane and the half width B of the diffraction peak obtained by the (104) plane in the powder X-ray diffraction pattern of the active material particle is expressed by the following equation : (A / B)? 0.7. 9. The method of claim 8,
Wherein the firing step is performed so that the firing time is 3 to 20 hours. 10. The method according to claim 8 or 9,
Wherein the firing step is performed so that the maximum firing temperature is from 850 캜 to 950 캜. 11. The method according to any one of claims 8 to 10,
Wherein the transition metal hydroxide comprises tungsten,
Wherein the content of tungsten is from 0.05 mol% to 1 mol% when assuming that the sum of all the transition metal elements other than tungsten in the transition metal hydroxide is 100 mol% as a mole percentage. The method according to any one of claims 8 to 11,
In the raw hydroxide producing step,
A nucleation step of precipitating the transition metal hydroxide from the aqueous solution,
Wherein the transition metal hydroxide is grown in a state where the pH of the aqueous solution is lower than the nucleation step,
Lt; / RTI &gt;
Wherein the pH of the aqueous solution in the nucleation step ranges from 12 to 13, and
Wherein the aqueous solution has a pH of 11 or more and less than 12 in the particle growth step.

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